The present embodiments relate to medical diagnostic ultrasound. In particular, ultrasound is used to estimate a viscoelastic parameter.
Conventional shear wave speed imaging uses an acoustic radiation force impulse (ARFI) or pushing pulse to generate shear waves. Ultrasound tracking at locations spaced laterally from the focus of the ARFI monitors the propagation of the shear wave away from the origin of the shear wave at the focus of the ARFI. Several factors affect the quality of the shear wave speed measurements, including loss of signal-to-noise ratio due to shear wave attenuation and spreading, reflections of the shear wave at boundaries and tissue heterogeneities, and motion artifacts due to transmission of multiple excitation pulses to track and/or increase the size of the imaging region. Furthermore, long cooling down times are necessary in order to stay within mechanical index (MI) and thermal United States Food and Drug Administration (FDA) limits.